Acoustic positioning of communication partner using code division multiplexing in a multipath environment for underwater acoustic communication with an acoustic lens system

Abstract This study investigates underwater acoustic (UWA) communication using an acoustic lens, which enables simple beamforming and potentially eliminates the need for complex signal processing. Accurate positioning of communication partners is essential for lens-based UWA communication, especially in multipath environments. To address this, we examine two positioning methods combining an acoustic lens with code division multiplexing (CDM): one utilizing time-of-flight and the other employing trigonometric calculations. Simulations based on a two-dimensional finite difference time domain method were conducted to evaluate proposed methods in multipath environments. The results indicate that both CDM-based approaches outperform conventional methods without CDM in terms of positioning accuracy. Although the evaluations were conducted under limited conditions, the proposed methods demonstrated sufficient accuracy to enable error-free and crosstalk-free communication. These findings suggest that CDM-based positioning methods are effective for identifying the optimal receiving element during communication.